Stacked-type piezoelectric device and method for manufacturing the same

ABSTRACT

A stacked-type piezoelectric device includes a stack of piezoelectric layers, plural conductive layers, a first contact hole, a second contact hole, and plural insulating portions. The piezoelectric layers are disposed between the conductive layers. The first and second contact holes penetrate the piezoelectric layers and the conductive layers, and each of first and second contact holes is filled with a conductive material. Every insulating portion is formed at one conductive layer. Two adjacent insulating portions are respectively formed at the outer rims of the first and second contact holes, to electrically isolate the conductive layer (in which the insulating portion is formed) from the conductive material in the contact hole.

This application claims the benefit of Taiwan application Serial No.98123514, filed Jul. 10, 2009, the subject matter of which isincorporated herein by reference.

BACKGROUND

1. Technical Field

The disclosure relates in general to a stacked-type piezoelectric deviceand a method for manufacturing the same, and more particularly to astacked-type piezoelectric device capable of reducing damage and thevolume and a method for manufacturing the same.

2. Description of the Related Art

Piezoelectric material has an asymmetric center in the crystal phase,which results in uneven charge distribution. After polarizationtreatment, the inputted voltage is converted into mechanicaldisplacement or deformation which generates electric current. When theinputted voltage is alternative current, the material vibratescorrespondingly and generates vibration waves. On the contrary, when thepiezoelectric membrane is pressed which generates deformation potentialenergy, the potential energy is converted into electric energy at themoment of release.

Due to the special characteristics of the material, the piezoelectricmaterial is suitable for being applied to many devices in people's dailylives, for energy saving and environmental protection. For example, whenthe piezoelectric device is applied to the lens of a compact electronicproduct, such as the lens of a camera phone, a constant voltage can beapplied to the piezoelectric device under the lens for causing constantexpansion, which drives the lens to perform the focus adjustment. Whenthe piezoelectric device is applied to an ultrasonic nebulizer, thepiezoelectric ceramic membrane generates high-frequency vibration waves,which break up water into extremely fine mist droplets and sends themist droplets to the air through the high-frequency vibration principleof the piezoelectric effect. Furthermore, through the piezoelectriceffect, the deformed piezoelectric material is able to generate electriccurrent. For example, the piezoelectric device is placed in the shockabsorbent material in the automobile engine. When the engine vibrates,the piezoelectric device is deformed which generates electric current.As a result, part of the energy is recycled to save energy. Otherexamples include consumer products and industrial supplies, such as theink droplet control in the inkjet printer, ultrasonic medical image,nondestructive testing for detecting the internal defects within thestructure . . . etc. However, most of the piezoelectric devices are madeof several sheets of stacked piezoelectric materials for higher drivingdeformation or greater electric current. The reasons include: (1) thedeformation of the piezoelectric materials is nonlinear, so it is easierto control the deformation when the piezoelectric materials are stackedtogether; and (2) less driving current is needed, which obtains betterfrequency response.

Please refer to FIG. 1. FIG. 1 illustrates a stacked-type piezoelectricactuator. Several vertically-stacked piezoelectric layers 2 areelectrically connected to each other and electrically conducted throughtwo lateral sides. When a low voltage is applied for driving the device,those piezoelectric layers 2 are deformed. As a result, the entireheight of the piezo stack increases to (L+ΔL) from the original stackingheight L.

Conventionally, when the stacked-type piezoelectric device is in use, aconductive surrounding structure or a frame which functions as a casingis required to fasten the piezoelectric materials. Please refer to FIG.2, which illustrates the structure of a conventional piezoelectricactuator. The piezoelectric actuator includes several vertically-stackedpiezoelectric layers 2, an electrode layers 3 disposed between thepiezoelectric layers 2, a frame 4 to fasten the piezoelectric layers 2and a contact layer 5 to conduct electricity to the electrode layers 3.The frame 4 is connected to the lateral sides of the piezoelectriclayers 2 and electrically connected to an external connector 6 through acopper wire 7. As shown in FIG. 2, an operating voltage is applied tothe connector 6, and the right half and the left half of the frame 4 areconnected to the positive and negative electrodes respectively. As aresult, the even-numbered and odd-numbered layers of the electrodelayers 3 which are counted from the top carry positive and negativecharge respectively. An electric field is generated correspondingly inthe center region M where electrode layers 3 overlap. Accordingly, thepiezoelectric layers 2 corresponding to the center region M deform andexpand. The expanding direction is indicated by the arrows. The portionof the piezoelectric layers 2 corresponding to the edge region R expandsless because there is no electric field effect there. Lateral ends ofthe piezoelectric layers 2 do not deform because being restrained by theframe 4.

However, the conventional piezoelectric actuator has some disadvantageswhen in practical use. The lateral ends of the piezoelectric layers 2are fastened by the frame 4. When the central portion of thepiezoelectric layers 2 deform, the total height of the lateral sidesremains the same. Therefore, tensile stress exists at the boundarybetween the central portion and the rim of the piezoelectric layers 2,which causes extremely uneven stress distribution. When the deformationis greater, the tensile stress becomes higher, which leads to fractureeasily. Furthermore, only part of the piezoelectric layers 2 whichcorresponds to the center region M is deformed effectively. In the edgeregion R where the electrodes do not overlap cannot effectively performpiezoelectric effect. Moreover, the frame 4 used for fastening thestacked piezoelectric layers 2 increases the entire volume of thepiezoelectric actuator, and the piezoelectric actuator becomes heavieraccordingly.

SUMMARY

According to the present disclosure, a stacked-type piezoelectric deviceis provided. The device includes several piezoelectric layers, severalconductive layers, the first and second contact holes and severalinsulating portions. The piezoelectric layers are disposed between theconductive layers. The first and second contact holes respectivelypenetrate the piezoelectric layers and the conductive layers. Aconductive material is filled in the first and second contact holes. Theinsulating portions are formed in the conductive layer correspondingly.Two adjacent insulating portions are respectively formed at the outerrims of the first and second contact holes, to electrically isolate theconductive layer in which the insulating portions are formed from theconductive material in the contact hole.

According to the present disclosure, a multi-layer stacked-typepiezoelectric device is provided. The device includes severalpiezoelectric units stacked together. Each piezoelectric unit includes apiezoelectric layer, the first and second conductive layers, the firstand second contact holes, and the first and second insulating portions.The piezoelectric layer has an upper surface and a lower surface. Thefirst and second conductive layers are respectively formed on the upperand lower surfaces of the piezoelectric layer. The first and secondcontact holes respectively penetrate two lateral sides of thepiezoelectric layer, and each of the contact holes is filled with aconductive material. The first and second insulating portions arerespectively formed in the first and second conductive layers on theupper and lower surfaces of the piezoelectric layer. Also, the first andsecond insulating portions are respectively formed at the outer rims ofthe first and second contact holes, for electrically isolating theconductive layer in which the insulating portions are formed from theconductive material in the contact hole. In an embodiment, the first andsecond contact holes respectively penetrate two lateral sides of thefirst conductive layer, the piezoelectric layer and the secondconductive layer. Furthermore, in the multi-layer stacked-typepiezoelectric device, one of the first and second insulating portions ofeach piezoelectric unit corresponds to and contacts one of the first andsecond insulating portions of an adjacent piezoelectric unit.

According to the present disclosure, a method for manufacturing amulti-layer stacked-type piezoelectric device is provided. First,several piezoelectric units are formed. Each piezoelectric unit includesa piezoelectric layer having an upper surface and a lower surface, thefirst and second conductive layers respectively formed on the upper andlower surfaces of the piezoelectric layer, the first and second contactholes respectively penetrating two lateral sides of the first conductivelayer, the piezoelectric layer and the second conductive layer, and thefirst and second insulating portions respectively formed in the firstand second conductive layers on the upper and lower surfaces of thepiezoelectric layer. Also, the first and second insulating portions arerespectively formed at the outer rims of the first and second contactholes. Next, the piezoelectric units are stacked, so that one of thefirst and second insulating portions of each piezoelectric unit contactsone of the first and second insulating portions of an adjacentpiezoelectric unit. After stacked, the first and second contact holesform the first and second channel. Then, conductive material is filledin the first and second channels respectively, so that the first andsecond channels with the conductive material respectively penetrate thepiezoelectric units.

According to the present disclosure, a method for manufacturing amulti-layer stacked-type piezoelectric device. First, several first andsecond insulated piezoelectric bodies are formed. Each of the first andsecond insulated piezoelectric bodies includes a piezoelectric layerhaving an upper surface and a lower surface, a conductive layer formedon the upper surface of the piezoelectric layer, and the first andsecond insulating portions respectively formed at a left half and aright half of the conductive layers of the first and second insulatedpiezoelectric bodies. Next, the first and second insulated piezoelectricbodies are stacked staggeredly for forming a stacked-type assembly.Then, the portions corresponding to the first and second insulatingmaterials of the stacked-type assembly are drilled, for forming thefirst and second channels. The size of the first and second channels isless than that of the first and second insulating materials. As aresult, the first and second insulating portions are formed respectivelyin the conductive layers of the first and second insulated piezoelectricbodies. Later, the first and second channels are respectively filledwith conductive material, so that the first and second channels with theconductive material respectively penetrate the insulated piezoelectricbodies.

According to the present disclosure, a method for manufacturing amulti-layer stacked-type piezoelectric device. First, several first andsecond piezoelectric bodies are formed. Each of the first and secondpiezoelectric bodies includes a piezoelectric layer having an uppersurface and a lower surface, and a conductive layer formed on the uppersurface of the piezoelectric layer. An first opening and an secondopening are formed respectively on each of the conductive layers of thefirst and second piezoelectric bodies. The first openings are formed atthe left half of the piezoelectric layers, and the second openings areformed at the right half of the piezoelectric layers. Next, the firstand second piezoelectric bodies are stacked staggeredly, for forming astacked-type assembly. Then, the stacked-type assembly corresponding tothe first and second openings is drilled to form the first and secondchannels. The size of the first and second channels is less than that ofthe first and second openings. Later, the first and second channels andthe first and second openings are filled with an insulating material.Thereon, the first and second channels are drilled again to remove theinsulating material in the first and second channels. After the drillingstep, the first and second insulating portions are formed in theconductive layers of the first and second piezoelectric bodies.Subsequently, the first and second channels are filled with conductivematerial.

The disclosure will become apparent from the following detaileddescription of the exemplary but non-limiting embodiments. The followingdescription is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (PRIOR ART) illustrates a stacked-type piezoelectric actuator;

FIG. 2 (PRIOR ART) illustrates the structure of a conventionalpiezo-actuator;

FIG. 3A illustrates a stacked-type piezoelectric device according to anexemplary embodiment of the present disclosure;

FIG. 3B illustrates another piezoelectric device according to theexemplary embodiment of the present disclosure;

FIG. 4A˜FIG. 4H show the flow of the method for manufacturing a singlepiezoelectric unit structure according to the first embodiment of thepresent disclosure;

FIG. 5A˜FIG. 5B illustrate the flow of a method for manufacturing astacked-type piezoelectric device according to the first embodiment ofthe present disclosure;

FIG. 6A˜FIG. 6B are the top views of FIG. 5A˜FIG. 5B respectively;

FIG. 7 illustrates the stacked-type piezoelectric device according tothe first embodiment of the present disclosure;

FIG. 8A˜FIG. 8H illustrate the flow of a method for manufacturing thestacked-type piezoelectric device according to the second embodiment ofthe present disclosure;

FIG. 9A˜FIG. 9G show the flow of a method for manufacturing thestacked-type piezoelectric device according to the third embodiment ofthe present disclosure;

FIG. 10 illustrates the stacked-type piezoelectric device according tothe third embodiment of the present disclosure; and

FIG. 11A˜FIG. 11H show the flow of the method for manufacturing astacked-type piezoelectric device according to the fourth embodiment ofthe present disclosure.

DETAILED DESCRIPTION

A stacked-type piezoelectric device including at least two piezoelectriclayers is provided by the present disclosure. Each piezoelectric layerhas at least two contact holes. A conductive layer is formed on at leastone surface of each piezoelectric layer. When stacked, severalpiezoelectric layers are staggered and rotated in a plane. As a result,the contact holes of the piezoelectric layers are aligned with eachother precisely. Conductive material is filled in the contact holes forforming micro-actuators having positive and negative electrodes. In astacked-type piezoelectric device of the present disclosure, thepiezoelectric layers are drilled and then filled with the conductivematerial for forming staggered positive and negative electrodes whichpenetrate the piezoelectric material. There is no need to use the framewhich is used in the conventional piezoelectric actuator to fasten thepiezoelectric material. The actuator deforms and expands evenly, whichresults in less damage and fractures due to excessive tensile stress.The size is reduced significantly, and the appearance is simplified.Therefore, a small-size actuator can be formed.

Four embodiments are provided for demonstrating the structure ofstacked-type piezoelectric device of the present disclosure and methodfor manufacturing the same. However, the embodiments disclosed hereinare used for illustrative purpose, but not for limiting the scope of thedisclosure. Also, it is known for people skill in the art that thestructure presented in the embodiments and drawings could be slightlymodified under the spirit of the disclosure. The specification and thedrawings are to be regard as an illustrative sense rather than arestrictive sense. Additionally, the drawings used for illustrating theembodiments and applications of the present disclosure only show themajor characteristic parts in order to avoid obscuring the presentdisclosure.

Please refer to FIG. 3A. FIG. 3A illustrates a stacked-typepiezoelectric device according to an embodiment of the presentdisclosure. The stacked-type piezoelectric device 10 includes severalpiezoelectric layers 11 a˜11 d, several conductive layers 13 a˜13 e, thefirst contact hole 15 a, the second contact hole 15 b and severalinsulating portions 16 a˜16 e. The piezoelectric layers 11 a˜11 d aredisposed between the conductive layers 13 a˜13 e. The first contact hole15 a and the second contact hole 15 b at least penetrate thepiezoelectric layers 11 a˜11 d. For example, the first contact hole 15 aand the second contact hole 15 b respectively penetrate two lateralsides of the piezoelectric layers 11 a˜11 d and the conductive layers 13a˜13 e. Each of the first contact hole 15 a and the second contact hole15 b is filled with conductive material. In an embodiment, the firstcontact hole 15 a and the second contact hole 15 b respectivelypenetrate two lateral sides of the piezoelectric layers 11 a˜11 d andthe conductive layers 13 a˜13 e vertically. However, the presentdisclosure does not limit the way that the contact holes penetrate thelayers.

The insulating portions 16 a˜16 e are respectively formed in theconductive layers 13 a˜13 e correspondingly. Two adjacent insulatingportions are formed at the outer rims of the first contact hole 15 a andthe second contact hole 15 b respectively, to electrically isolate theconductive layer in which the insulating portion is formed from theconductive material in the contact hole. For example, the insulatingportion 16 a is formed in the conductive layer 13 a, and the insulatingportion 16 b is formed in the conductive layer 13 b. The two adjacentinsulating portions 16 a and 16 b are at the outer rims of the firstcontact hole 15 a and the second contact hole 15 b respectively. As aresult, the conductive layers 13 a and 13 b are electrically isolatedfrom the conductive materials in the first contact hole 15 a and thesecond contact hole 15 b due to the existence of the insulating portions16 a and 16 b. Similarly, the conductive layers 13 c and 13 e areelectrically isolated from the conductive material in the first contacthole 15 a due to the existence of the insulating portions 16 c and 16 e.The conductive layer 13 d is electrically isolated from the conductivematerial in the second contact hole 15 b due to the existence of theinsulating portion 16 d.

Furthermore, although different patterns are used in FIG. 3A forrepresenting the locations of the first contact hole 15 a, the secondcontact hole 15 b and the conductive layers 13 a˜13 c, the conductivematerial in the first contact hole 15 a and the second contact hole 15 bcan be the same as or different from the conductive material of theconductive layers 13 a˜13 c practically. The present disclosure is notlimited thereto.

When the stacked-type piezoelectric device 10 in FIG. 3A is in use, thefirst contact hole 15 a and the second contact hole 15 b can beelectrically connected with the negative and positive electrodes of asource respectively. When an operating voltage is applied to thestacked-type piezoelectric device 10, the first contact hole 15 a andthe conductive layers 13 d and 13 b carry negative charge, and thesecond contact hole 15 b and the conductive layers 13 e, 13 c and 13 acarry positive charge. As a result, the piezoelectric layers 11 a˜11 dbetween the conductive layers 13 a˜13 e deform and expand along thedirections indicated by the arrows.

The stacked-type piezoelectric device 10 does not have the frame whichis used in the conventional piezoelectric actuator for fastening thepiezoelectric layers. Therefore, the piezoelectric layers 11 a˜11 d areable to expand evenly in a plane with less damage due to excessivetensile stress. Moreover, the first contact hole 15 a and the secondcontact hole 15 b only occupy a small area of the piezoelectric layers11 a˜11 d. As a result, for the piezoelectric layers of the same size,the stacked-type piezoelectric device 10 of the present disclosure haslarger ratio of the effect area to perform piezoelectric effect than theconventional piezoelectric actuator. Besides, as to the appearance ofboth devices, the volume of the stacked-type piezoelectric device 10 ofthe present disclosure only includes the stacked piezoelectric layers 11a˜11 d and the conductive layers 13 a˜13 e. Therefore, compared to theconventional piezoelectric actuator which needs a fastening frame, thedevice of the present disclosure has much less volume.

Please refer to FIG. 3B. FIG. 3B illustrates a piezoelectric deviceaccording to another exemplary embodiment of the present disclosure. Theidentical components shown in FIG. 3B and FIG. 3A are denoted as thesame reference numbers. Compared to the device in FIG. 3A, the device inFIG. 3B has similar structure except that the device in FIG. 3B furtherincludes several insulation sidewalls 17 b˜17 e which are connected tothe insulating portions 16 b˜16 e perpendicularly. Also, the insulationsidewalls 17 b˜17 e are located between the piezoelectric layers and thefirst and second contact holes 15 a and 15 b, to electrically isolatethe piezoelectric layers from the conductive material in the contactholes 15 a and 15 b. When an operating voltage is applied to thestacked-type piezoelectric device 20, the insulation sidewalls 17 b˜17 eprevent the piezoelectric layers 11 a˜11 d from lateral deformation andexpansion. As a result, the piezoelectric layers 11 a˜11 d only expandalong the direction indicated by the arrows.

For example, the insulation sidewall 17 b connected to the insulatingportion 16 b is located between the piezoelectric layer 11 a and thesecond contact hole 15 b, to electrically isolate the piezoelectriclayer 11 a from the conductive material in the second contact hole 15 b.Similarly, the insulation sidewall 17 d electrically isolates thepiezoelectric layer 11 c from the conductive material in the secondcontact hole 15 b. The insulation sidewall 17 c electrically isolatesthe piezoelectric layer 11 b from the conductive material in the firstcontact hole 15 a. The insulation sidewall 17 e electrically isolatesthe piezoelectric layer 11 d from the conductive material in the firstcontact hole 15 a.

Although the stacked-type piezoelectric devices in FIG. 3B and FIG. 3Ainclude four piezoelectric layers 11 a˜11 d as examples, the presentdisclosure does not limit the number of the piezoelectric layers. Thepresent disclosure encompasses the stacked-type piezoelectric deviceshaving at least two piezoelectric layers. In other words, thestacked-type piezoelectric device provided by the present disclosureincludes n piezoelectric layers and (n+1) conductive layers. n is anpositive integer not less than 2. The piezoelectric layers are staggeredbetween the conductive layers. The insulating portions of theodd-numbered conductive are corresponding to the outer rims of the firstcontact hole. The insulating portions of the even-numbered conductivelayers are corresponding to the outer rims of the second contact hole.

Several exemplary embodiments are provided by the present disclosureaccording to the above-described piezoelectric device for illustratingat least four methods for manufacturing the stacked-type piezoelectricdevice. However, the detailed steps of the manufacturing methods and thestructures revealed in the embodiments are used as examples and not tolimit the present disclosure. Moreover, the drawings of the embodimentsonly show the components related to the present disclosure. Unnecessarycomponents are neglected for clarity.

First Embodiment

In the first embodiment, several piezoelectric unit structures aremanufactured first. Conductive layers are formed on the upper and lowersurfaces of the piezoelectric layers in each piezoelectric unitstructure, and the contact holes penetrate the structure vertically.Then, the piezoelectric unit structures are stacked together, and theconductive material is filled in the contact holes. Insulation sidewallsand insulating portions are formed in each piezoelectric unit structureas shown in FIG. 3B.

Please refer to FIG. 4A˜4H, which show the flow of the method formanufacturing a single piezoelectric unit structure according to thefirst embodiment of the present disclosure.

As shown in FIG. 4A, a piezoelectric layer 31 is provided first, and thepiezoelectric layer 31 has an upper surface 31 a and a lower surface 31b. Next, the first penetrating hole 311 a and the second penetratinghole 311 b are formed on both sides of the piezoelectric layer 31, andthe insulating materials 32 a and 32 b are filled in the firstpenetrating hole 311 a and the second penetrating hole 311 brespectively, as shown in FIG. 4B. The first penetrating hole 311 a andthe second penetrating hole 311 b vertically penetrate the piezoelectriclayer 31. After the insulating materials 32 a and 32 b are filled in thefirst penetrating hole 311 a and the second penetrating hole 311 b, thesurfaces of the insulating materials 32 a and 32 b are aligned with theupper and lower surfaces 31 a and 31 b of the piezoelectric layer 31respectively. The insulating materials 32 a and 32 b may benon-conductive adhesive, such as epoxy or other non-conductivematerials. The shape of the first penetrating hole 311 a and the secondpenetrating hole 311 b has no limitation and can be a circle, ellipse,rectangle or any other shape. In the present embodiment, the firstpenetrating hole 311 a and the second penetrating hole 311 b arecircular as an example and has the same penetrating diameter L₁.

Then, as shown in FIG. 4C, the first conductive layer 33 is formed onthe upper surface 31 a of the piezoelectric layer 31. Subsequently, asshown in FIG. 4D, the piezoelectric layer 31 is turned upside down, andthe second conductive layer 34 is formed on the lower surface 31 b ofthe piezoelectric layer 31. The first and second conductive layers 33and 34 cover the insulating materials 32 a and 32 b respectively.

Thereon, as shown in FIG. 4E, the first contact hole 35 a and the secondcontact hole 35 b are formed corresponding to the first penetrating hole311 a and the second penetrating hole 311 b respectively by drilling.The diameter L₂ of the drilled first contact hole 35 a and the secondcontact hole 35 b is less than the diameter L₁ of the first penetratinghole 311 a and the second penetrating hole 311 b. The first insulatingsidewall 37 a and the second insulating sidewall 37 b are formedaccordingly. The first contact hole 35 a and 35 b vertically penetratethe second conductive layer 34, the piezoelectric layer 31 and the firstconductive layer 33 respectively.

Later, a portion of the conductive layers on the upper and lower sidesof the piezoelectric layer 31 corresponding to the outer rims of thefirst contact hole 35 a and the second contact hole 35 b is removed. Asshown in FIG. 4F, a portion of the second conductive layer 34corresponding to the outer rim of the first contact hole 35 a is removedfor forming an opening 341. A portion of the first conductive layer 33corresponding to the outer rim of the second contact hole 35 b isremoved for forming an opening 331. The diameter L₃ of the openings 331and 341 is larger than the diameter L₂ of the first contact hole 35 aand the second contact hole 35 b and the diameter L₁ of the firstpenetrating hole 311 a and the second penetrating hole 311 b. Also,there is no limitation on the shape of the openings 331 and 341. Theopenings 331 and 341 can be circular, elliptical, rectangular or anyother shape.

Then, as shown in FIG. 4G, the insulating materials 38 a and 38 b arefilled in the first contact hole 35 a and the second contact hole 35 b.Also, the insulating material 38 a and 38 b are fully filled in theopenings 331 and 341. The surfaces of the insulating materials 38 a and38 b are aligned with the upper and lower surfaces of the first andsecond conductive layers 33 and 34 respectively.

Next, as shown in FIG. 4H, drilling is performed on the first contacthole 35 a and the second contact hole 35 b for leaving the insulatingmaterial at the outer rims of the first contact hole 35 a and the secondcontact hole 35 b to form the first insulating portion 39 a and thesecond insulating portion 39 b. After drilling, the first insulationsidewall 37 a is located between the first contact hole 35 a and thepiezoelectric layer 31 and connected to the first insulating portion 39a. The second insulation sidewall 37 b is located between the secondcontact hole 35 b and the piezoelectric layer 31 and connected to thesecond insulating portion 39 b. Furthermore, one end of the firstinsulation side wall 37 a is aligned with the lower surface 31 a of thepiezoelectric layer 31, and one end of the second insulation side wall37 b is aligned with the upper surface 31 b of the piezoelectric layer31. As to the selection of the material, the insulating materials 38 aand 38 b of the first and second insulating portions 39 a and 39 b canbe the same as or different from the insulating materials 32 a and 32 bof the first and second insulation sidewalls 37 a and 37 b, whichdepends on the practical conditions. The present disclosure is notlimited thereto.

Following the above-described steps in FIG. 4A˜4H, a piezoelectric unitstructure 40 can be manufactured accordingly.

Next, several piezoelectric unit structures 40 in FIG. 4H are stackedvertically. The conductive materials are filled in the contact holes toform a multi-layer stacked-type piezoelectric device. Thus, thedeformation driven by the piezoelectric device when in use is increased,or greater electric current is generated. When stacked in a staggeredmanner, the piezoelectric unit structure 40 is laterally rotated 180°and then stacked on another piezoelectric unit structure 40.

FIG. 5A˜FIG. 5B illustrate the flow of a method for manufacturing astacked-type piezoelectric device according to the first embodiment ofthe present disclosure. FIG. 6A˜FIG. 6B are the top views of FIG.5A˜FIG. 5B respectively. Please refer to FIG. 5A˜FIG. 5B and FIG.6A˜FIG. 6B at the same time. Five piezoelectric unit structures in FIG.4G are stacked as an example for illustrating the present embodiment.

As shown in FIG. 5A and FIG. 6A, several piezoelectric unit structures401˜405 are stacked vertically. When stacked, one piezoelectric unitstructure is laterally rotated 180° and then stacked on anotherpiezoelectric unit structure. For example, after laterally rotated 180°,the first contact hole 35 a of the piezoelectric unit structure 402 isaligned with the second contact hole 35 b of the lower adjacentpiezoelectric unit structure 401. Similarly, the first contact hole 35 aof the piezoelectric unit structure 404 is aligned with the secondcontact hole 35 b of the lower adjacent piezoelectric unit structure403. Also, as shown in FIG. 5A, the first insulating portion 39 a of thestacked piezoelectric unit structure 403 contacts the second insulatingportion 39 b of the upper adjacent piezoelectric unit structure 404. Thefirst contact holes 35 a and the second contact holes 35 b of thestacked piezoelectric unit structures 401˜405 form the first channelR_(H) and the second channel L_(H).

Later, as shown in FIG. 5B and FIG. 6B, the conductive materials 501 aand 501 b are filled in the first channel R_(H) and the second channelL_(H) respectively for forming a stacked-type piezoelectric device 50.The first channel R_(H) and the second channel L_(H) verticallypenetrate the piezoelectric unit structures 401˜405. The conductivematerials 501 a and 501 b may be conductive adhesive (such as silverpaste) or tin/lead solder for example.

FIG. 7 illustrates the stacked-type piezoelectric device according tothe first embodiment of the present disclosure. When the stacked-typepiezoelectric device 50 in FIG. 5B is in practical use, the conductivematerial 501 a in the first channel R_(H) and the conductive material501 b in the second channel L_(H) are electrically connected to thenegative and positive electrodes of an external source respectively.When an operating voltage is applied to the stacked-type piezoelectricdevice 50, the piezoelectric layers between the electrode layers deformand expand along the directions indicated by the arrows. Anyone who hasordinary skill in the field of the present disclosure can understandthat when in practical use, a constant voltage can be applied to thestacked-type piezoelectric device 50 for generating specificdeformation. Or, an alternative current can be applied to thestacked-type piezoelectric device 50 for generating high-frequencyvibration. Or, the stacked-type piezoelectric device 50 is deformed togenerate electric current. Modification can be made depending on thepractical conditions.

The piezoelectric unit structure in FIG. 4H manufactured following thesteps in FIG. 4A˜FIG. 4H mainly includes the piezoelectric layer 31, thefirst and second conductive layers 33 and 34 respectively formed aboveand under the piezoelectric layer 31, the first and second contact holes35 a and 35 b vertically penetrating the piezoelectric layer 31, thefirst conductive layer 33 and the second conductive layer 34, the firstand second insulating portions 39 a and 39 b respectively formed in thefirst and second conductive layers 33 and 34 respectively surroundingthe outer rims of the first and second contact holes 35 a and 35 b, andthe first and second insulation sidewalls 37 a and 37 b respectivelyconnected to the first and second insulating portions 39 a and 39 b.What is worth mentioning is that when the conductive materials aredirectly filled in the first and second contact holes 35 a and 35 b, apiezoelectric device with a single-layer piezoelectric layer can beformed accordingly.

A stacked-type piezoelectric device 50 can be formed by stacking thepiezoelectric unit structures as shown in FIG. 4H following the steps inFIG. 5A˜FIG. 5B. Piezoelectric effect occurs in the piezoelectric layers31 under the action of the electric field due to the locations of thefirst and second insulating portions 39 a and 39 b and the first andsecond insulation sidewalls 37 a and 37 b. FIG. 7 shows the polarity ofeach piezoelectric layer and the first and second conductive layers ofthe device 50 when the conductive materials 501 a and 501 b respectivelyin the first channel R_(H) and the second channel L_(H) are electricallyconnected to the negative and positive electrodes of an external source.The insulating portions are used for electrically isolating theconductive layers from the conductive materials in some of the adjacentcontact holes. The insulating sidewalls are used for electricallyisolating the piezoelectric layers from the conductive materials in theadjacent contact holes.

What is worth mentioning is that although the conductive layers areformed on the upper and lower surfaces of each piezoelectric unitstructure in the stacked-type piezoelectric device 50, the two adjacentconductive layers between the stacked piezoelectric layers in FIG. 7 canstill be considered to be a single layer, compared to the structure inFIG. 3B. Therefore, the present disclosure encompasses the stacked-typepiezoelectric device 50 according to the first embodiment of the presentdisclosure.

Second Embodiment

In the second embodiment, several piezoelectric unit structures withconductive layers on both the upper and lower surfaces and the contactholes penetrating the structure are formed first, which is the same asthe first embodiment. Next, the piezoelectric unit structures arestacked, and the conductive materials are filled in the contact holes.The difference between the second and first embodiments is that only theinsulating portion but no insulation sidewall is formed in thepiezoelectric unit structure according to the second embodiment. Thestacked-type piezoelectric device according to the second embodiment isencompassed by the technical field in FIG. 3A of the present disclosure.

Please refer to FIG. 8A˜FIG. 8H, which illustrate the flow of a methodfor manufacturing the stacked-type piezoelectric device according to thesecond embodiment of the present disclosure.

First, as shown in FIG. 8A, a piezoelectric layer 61 is provided. Thepiezoelectric layer 61 has an upper surface 61 a and a lower surface 61b. Next, as shown in FIG. 8B, the first conductive layer 63 and thesecond conductive layer 64 are respectively formed on the upper andlower surfaces 61 a and 61 b of the piezoelectric layer 61.

Then, as shown in FIG. 8C, the first penetrating hole 611 a and thesecond penetrating hole 611 b are respectively formed on both sides ofthe piezoelectric layer 61. The first penetrating hole 611 a and thesecond penetrating hole 611 b vertically penetrate the second conductivelayer 64, the piezoelectric layer 61 and the first conductive layer 63.There is no limitation on the shape of the penetrating holes 611 a and611 b. In the present embodiment, the first penetrating hole 611 a andthe second penetrating hole 611 b are circular and have the samepenetrating diameter L₄ as an example.

Subsequently, as shown in FIG. 8D, a portion of the conductive layersabove and under the piezoelectric layer 61 corresponding to the firstand second penetrating holes 611 a and 611 b is removed. For example, aportion of the second conductive layer 64 corresponding to the firstpenetrating hole 611 a is removed to form an opening 641. A portion ofthe first conductive layer 63 corresponding to the second penetratinghole 611 b is removed to form an opening 631. The diameter L₅ of theopenings 631 and 641 is larger than the diameter L₄ of the first andsecond penetrating holes 611 a and 611 b. Moreover, there is nolimitation on the shape of the openings 631 and 641. The openings 631and 641 can be circular, elliptical, rectangular or any other shape.

Later, as shown in FIG. 8E, the insulating materials 62 a and 62 b arefilled in the first and second penetrating holes 611 a and 611 b. Theinsulating materials 62 a and 62 b are also fully filled in the openings631 and 641. The exposed surfaces of the insulating materials 62 a and62 b are aligned with the upper and lower surfaces of the first andsecond conductive layers 63 and 64 after the filling step. Theinsulating materials 62 a and 62 b are non-conductive adhesive forexample, such as epoxy or other non-conductive materials.

Thereon, as shown in FIG. 8F, the places corresponding to the first andsecond penetrating holes 611 a and 611 b are drilled to form the firstand second contact holes 65 a and 65 b respectively. The diameter L₄ ofthe first and second contact holes 65 a and 65 b is the same as thediameter L₄ of the first and second penetrating holes 611 a and 611 b.The first and second contact holes 65 a and 65 b vertically penetratethe second conductive layer 64, the piezoelectric layer 61 and the firstconductive layer 63 respectively. After the drilling step, theinsulating materials are left at the places corresponding to the outerrims of the first and second contact holes 65 a and 65 b to form thefirst and second insulating portions 66 a and 66 b. The first and secondinsulting portions 66 a and 66 b are respectively on the upper and lowersides of the piezoelectric layer 61.

A piezoelectric unit structure is formed following the steps in FIG.8A˜FIG. 8F.

Then, as shown in FIG. 8G, several piezoelectric unit structures 701˜705in FIG. 8F are stacked vertically. When stacked, the piezoelectric unitstructure is laterally rotate 180° and then stacked on anotherpiezoelectric unit structure. For example, after laterally rotated 180°,the first contact hole 65 a of the piezoelectric unit structure 702 isaligned with the second contact hole 65 b of the lower adjacentpiezoelectric unit structure 701. Similarly, the first contact hole 65 aof the piezoelectric unit structure 704 is aligned with the secondcontact hole 65 b of the lower adjacent piezoelectric unit structure703. Also, the first insulating portion 66 a of the stackedpiezoelectric unit structure contacts the second insulating portion 66 bof the adjacent piezoelectric unit structure. For example, the firstinsulating portion 66 a of the piezoelectric unit structure 703 contactsthe second insulating portion 66 b of the upper adjacent piezoelectricunit structure 704. The first contact holes 65 a and the second contactholes 65 b of the stacked piezoelectric unit structures 701˜705 form thefirst channel R_(H) and the second channel L_(H).

Later, as shown in FIG. 8H, the conductive materials 72 a and 72 b arefilled in the first channel R_(H) and the second channel L_(H)respectively for forming a stacked-type piezoelectric device 70. Thefirst channel R_(H) and the second channel L_(H) with the conductivematerials 72 a and 72 b vertically penetrate the piezoelectric unitstructures 701˜705 respectively. The conductive materials 72 a and 72 bmay be conductive adhesive (such as silver paste) or tin/lead solder.

What is worth mentioning is that when the conductive materials aredirectly filled in the first and second contact holes 65 a and 65 b ofthe piezoelectric unit structures in FIG. 8F, a single-layerpiezoelectric device is formed accordingly. When in use, thestacked-type piezoelectric device 70 in FIG. 8H has larger deformationor generates greater electric current. Although the second embodimentdoes not have the first and second insulation sidewalls 37 a and 37 b ofthe first embodiment (ex. FIG. 4H), each insulating portion is used forisolating the conductive layer from the conductive material in one ofthe adjacent contact hole. Therefore, effective deformation occurs alongthe vertical direction under the action of electric field.

What is worth mentioning is that although the conductive layers areformed on the upper and lower surfaces of each piezoelectric unitstructure in the stacked-type piezoelectric device 70 in FIG. 8H, thetwo adjacent conductive layers between the stacked piezoelectric layersin FIG. 8H can be considered to be a single layer. Therefore, the secondembodiment is encompassed by the field of the technical features in FIG.3A of the present disclosure.

Third Embodiment

In the first and second embodiments, the conductive layers are formed onboth the upper and lower surfaces of each piezoelectric layer. However,in the third embodiment, the conductive layer is formed on only onesurface of the piezoelectric layer. Next, the insulating portion isformed on the conductive layer. Then, stacking, drilling and conductivematerial filling steps are performed for conducting electricity in orderto form the stacked-type piezoelectric device.

Please refer to FIG. 9A˜FIG. 9G, which show the flow of a method formanufacturing the stacked-type piezoelectric device according to thethird embodiment of the present disclosure. As shown in FIG. 9A, apiezoelectric layer 81 is provided first. The piezoelectric layer 81 hasan upper surface 81 a and a lower surface 81 b. Then, a conductive layer82 (to be the electrode layer) is formed on one of the surfaces of thepiezoelectric layer 81, such as the upper surface 81 a in FIG. 9B, andan opening 821 is formed on the conductive layer 82 adjacent to oneside, such as the left side (or the right side). The opening 821 exposesthe upper surface 81 a of the piezoelectric layer 81 under the opening821. There is no limitation on the shape of the opening 821. The opening821 can be circular, elliptical, rectangular, or any other shape. In thepresent embodiment, the opening is circular as an example, and thediameter of the opening 821 is L₆.

Next, as shown in FIG. 9C, the insulating material 83 is formed in theopening 821. After the insulating material 83 is filled in the opening821, the surface of the insulating material 83 is aligned with thesurface of the conductive layer 82. The insulating material 83 is forexample a non-conductive adhesive, such as epoxy or anothernon-conductive material. When in practical use, the insulating material83 can be filled in the opening 821 by many different methods, such ashigh temperature coating (for example, the temperature is greater than700° C.). However, the present disclosure is not limited thereto. Aninsulating piezoelectric body P is formed by following the steps shownin FIG. 9A˜FIG. 9C.

Then, as shown in FIG. 9D, several piezoelectric bodies P as shown inFIG. 9C are stacked vertically. When stacked in a staggered manner, oneinsulating piezoelectric body P is laterally rotate 180° and thenstacked on another piezoelectric body P for forming a stacked-typeassembly. Take FIG. 9D for example. The insulating material 83 of twoadjacent insulating piezoelectric bodies, such as P1 and P2, arerespectively formed on the right half and left half of the conductivelayers 82 respectively. Along the vertical direction, the location ofthe insulating material 83 of the insulating piezoelectric body P4 iscorresponding to the location of the insulating material 83 of theinsulating piezoelectric body P2. The location of the insulatingmaterial 83 of the piezoelectric body P3 is corresponding to thelocation of the insulating material 83 of the piezoelectric body P1.

Then, as shown in FIG. 9E, hot-pressing sintering is performed on thestacked insulating piezoelectric bodies P1˜P4 for forming a stacked-typeassembly S₁.

Thereon, portions of the stacked-type assembly S₁ which correspond tothe insulating material 83 is drilled to form the first channel R_(H)and the second channel L_(H), as shown in FIG. 9F. There is nolimitation on the shape of the channel formed by drilling. In thepresent embodiment, the channel is circular, and the diameter is L₇ asan example. Therefore, after the drilling step, the insulating portions85 are formed on the conductive layers 82 of the insulatingpiezoelectric bodies P1˜P4.

Later, as shown in FIG. 9G, the conductive materials 86 a and 86 b arefilled in the first channel R_(H) and the second channel L_(H), forforming a stacked-type piezoelectric device. The first channel R_(H) andthe second channel L_(H) with the conductive materials 86 a and 86 brespectively penetrate the insulated piezoelectric bodies P1˜P4. Theconductive materials 86 a and 86 b are for example elastic conductivematerials (such as conductive adhesive or silver paste) or tin/leadsolder. The step of filling the conductive materials 86 a and 86 b canbe performed by chemical-plating, electroplating, photolithographyprocess or any other practical method. The present disclosure is notlimited thereto.

FIG. 10 illustrates the stacked-type piezoelectric device according tothe third embodiment of the present disclosure. When the stacked-typepiezoelectric device manufactured by the steps in FIG. 9A˜FIG. 9G is inpractical use, the conductive material 86 a in the first channel R_(H)and the conductive material 86 b in the second channel L_(H) arerespectively connected to the positive and negative electrodes of anexternal power source. The insulating portion 85 is used for isolatingthe conductive layers from the conductive material (86 a or 86 b) in oneof the adjacent channel. FIG. 10 shows the polarity of each conductivelayer. When a constant voltage is applied to the stacked-typepiezoelectric device in FIG. 10 in practical use, the piezoelectriclayers 81 between the conductive layers 82 deform and expand along thedirections indicated by the arrows.

Furthermore, the stacked-type piezoelectric device manufacturedaccording to the third embodiment of the present disclosure isencompassed by the field of the technical features in FIG. 3A of thepresent disclosure.

Fourth Embodiment

The method of the fourth embodiment is slightly different from that ofthe third embodiment, but the structures of the stacked-typepiezoelectric devices are the same which are encompassed by the field ofthe technical features in FIG. 3A of the present disclosure. In thefourth embodiment, the stacked piezoelectric bodies are drilled, filledwith the insulating material, drilled again and filled with theconductive material for conducting electricity in order to form astacked-type piezoelectric device. Furthermore, the components of thefourth embodiment which are the same as those of the third embodimentuse the same reference numbers for easier illustration.

Please refer to FIG. 11A˜FIG. 11H, which show the flow of the method formanufacturing a stacked-type piezoelectric device according to thefourth embodiment of the present disclosure. First, as shown in FIG.11A, a piezoelectric layer 81 is provided. The piezoelectric layer 81has an upper surface 81 a and a lower surface 81 b. Next, a conductivelayer 82 (to be the electrode layer) is formed on one surface of thepiezoelectric layer 81, such as the upper surface 81 a in FIG. 11B, andan opening 821 is formed on the conductive layer 82 adjacent to oneside, such as the left side (or the right side), of the piezoelectriclayer 81. The opening 821 can be circular, elliptical, rectangular, orany other shape. In the present embodiment, the opening is circular asan example, and the diameter of the opening 821 is L₆.

Next, as shown in FIG. 11C, several piezoelectric bodies Q as shown inFIG. 11B are stacked vertically. When stacked in a staggered manner, oneinsulating piezoelectric body Q is laterally rotate 180° and thenstacked on another piezoelectric body Q for forming a stacked-typeassembly. Take FIG. 11C for example. The openings 821 of two adjacentpiezoelectric bodies, such as Q1 and Q2, are respectively formed on theright half and left half of the conductive layer 82. Along the verticaldirection, the location of the opening 821 of the piezoelectric body Q4is corresponding to the location of the opening 821 of the piezoelectricbody Q2. The location of the opening 821 of the piezoelectric body Q3 iscorresponding to the location of the opening 821 of the piezoelectricbody Q1.

Subsequently, as shown in FIG. 11D, hot-pressing sintering is performedon the stacked piezoelectric bodies Q1˜Q4 for forming a stacked-typeassembly S₂.

Thereon, a portion of the stacked-type assembly S₂ which corresponds tothe opening 821 is drilled to form the first channel R_(H) and thesecond channel L_(H), as shown in FIG. 11E. There is no limitation onthe shape of the channel formed by drilling. In the present embodiment,the channel is circular, and the diameter is L₈ as an example. Thediameter L₈ of the channel is less than the diameter L₆ of the opening821.

Later, as shown in FIG. 11F, the insulating materials 84 a and 84 b arefilled in the first channel R_(H), the second channel L_(H) and theopening 821. After the filling step, the surfaces of the insulatingmaterials 84 a and 84 b are aligned with the surface of the conductivelayer 82. For example, the insulating materials 84 a and 84 b may benon-conductive adhesive, such as epoxy or another non-conductivematerial.

Next, as shown in FIG. 11G, the first channel R_(H) and the secondchannel L_(H) are drilled again for removing the insulating materials inthe first channel R_(H) and the second channel L_(H). The insulatingportions 85 are formed in the conductive layers 82 of the piezoelectricbodies Q1˜Q4. The diameter of the drilled holes is L₈.

Later, as shown in FIG. 11H, the conductive materials 86 a and 86 b arerespectively filled in the first channel R_(H) and the second channelL_(H), for forming a stacked-type piezoelectric device. The firstchannel R_(H) and the second channel L_(H) with the conductive materials86 a and 86 b vertically penetrate the piezoelectric bodies Q1˜Q4respectively. The conductive materials 86 a and 86 b are for exampleelastic conductive materials (such as conductive adhesive or silverpaste) or tin/lead solder. The step of filling the conductive materials86 a and 86 b can be performed by chemical-plating, electroplating,photolithography process or any other practical method. The presentdisclosure is not limited thereto.

When the stacked-type piezoelectric device in FIG. 11H is in practicaluse, the conductive materials 86 a filled in the first channel R_(H) andthe conductive material 86 b filled in the second channel L_(H) arerespectively connected to the positive and negative electrodes of anexternal power source. The insulating portions 85 are used for isolatingthe conductive layers from the conductive material (86 a or 86 b) in theadjacent channel. When a constant voltage is applied to the stacked-typepiezoelectric device in practical use, the piezoelectric layers 81between the conductive layers 82 deform and expand along the directionsindicated by the arrows.

In the stacked-type piezoelectric devices according to the first tofourth embodiments of the present disclosure, the piezoelectric materialis drilled and then filled with the conductive material to form thepiezoelectric device with staggered positive and negative electrodes.Whether the device according to the embodiments has the structure inFIG. 3A or FIG. 3B, there is no need to use the frame which is usedconventionally for fastening the piezo-actuator. As a result, the planardriving material expands and deforms evenly, and the piezoelectric layerdoes not crack easily due to excessive tensile stress. Furthermore, thesize of the device is reduced greatly, and the appearance is simplified.Therefore, a compact actuator can be manufactured accordingly.

The disclosure is directed to a stacked-type piezoelectric device and amanufacturing method thereof. When in practical use, the manufacturedpiezoelectric materials of the piezoelectric device deforms evenly in aplane, which reduces the possibility of damage and fracture. Also, theappearance of the device is simplified, and the volume is decreasedgreatly.

While the disclosure has been described by way of example and in termsof a exemplary embodiment, it is to be understood that the disclosure isnot limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A piezoelectric unit structure, comprising: a piezoelectric layer,having an upper surface and a lower surface; a first conductive layerand a second conductive layer, respectively located on the upper andlower surfaces of the piezoelectric layer; a first contact hole,penetrating the piezoelectric layer; a second contact hole, penetratingthe piezoelectric layer; and at least an insulating portion formed inone of the first and second conductive layers and surrounding one of thefirst and second contact holes, for isolating the contact hole from theconductive layer in which the insulating portion is formed.
 2. Thepiezoelectric unit structure according to claim 1, wherein the firstcontact hole penetrates one side of the first conductive layer, thepiezoelectric layer and the second conductive layer, and the secondcontact hole penetrates the other side of the first conductive layer,the piezoelectric layer and the second conductive layer.
 3. Thepiezoelectric unit structure according to claim 2, wherein the firstcontact hole and the second contact hole are perpendicular to the firstconductive layer, the piezoelectric layer and the second conductivelayer respectively.
 4. The piezoelectric unit structure according toclaim 2 further comprising another insulating portion, wherein the twoinsulating portions are respectively formed on the first conductivelayer and the second conductive layer on the upper and lower surfaces ofthe piezoelectric layers, and the two insulating portions respectivelysurround the outer rims of the first and second contact holes of theconductive layers.
 5. The piezoelectric unit structure according toclaim 2, wherein the first and second contact holes are filled with aconductive material.
 6. The piezoelectric unit structure according toclaim 5 further comprising an insulation sidewall connected to theinsulating portion and located between the piezoelectric layer and theconductive material, for electrically isolating the piezoelectric layerand the conductive material in the contact hole.
 7. The piezoelectricunit structure according to claim 5 comprising: a first insulatingportion, formed in the first conductive layer and at the outer rim ofthe first contact hole, to electrically isolate the first conductivelayer from the conductive material in the first contact hole; and asecond insulating portion, formed in the second conductive layer and atthe outer rim of the second contact hole, to electrically isolate thesecond conductive layer from the conductive material in the secondcontact hole.
 8. The piezoelectric unit structure according to claim 7further comprising: a first insulation sidewall, connected to the firstinsulating portion and electrically isolating the conductive material inthe first contact hole from the piezoelectric layer; and a secondinsulation sidewall, connected to the second insulating portion andelectrically isolating the conductive material in the second contacthole from the piezoelectric layer.
 9. The piezoelectric unit structureaccording to claim 8, wherein an end of the first insulation sidewall isaligned with the lower surface of the piezoelectric layer, and an end ofthe second insulation sidewall is aligned with the upper surface of thepiezoelectric layer.
 10. A multi-layer stacked-type piezoelectricdevice, comprising: a plurality of piezoelectric units stacked together,each of the piezoelectric units comprising: a piezoelectric layer,having an upper surface and a lower surface; a first conductive layerand a second conductive layer, respectively located on the upper andlower surfaces of the piezoelectric layer; a first contact hole and asecond contact hole, respectively penetrating two lateral sides of thefirst conductive layer, the piezoelectric layer and the secondconductive layer, wherein the first contact hole and the second contacthole are filled with a conductive material; and a first insulatingportion and a second insulating portion, respectively formed on thefirst and second conductive layers on the upper and lower surfaces ofthe piezoelectric layer and located at the outer rims of the first andsecond contact holes, for electrically isolating the conductive layer inwhich the insulating portions are formed from the conductive material inthe contact hole; wherein in the multi-layer stacked-type piezoelectricdevice, the first or second insulating portion of each piezoelectricunit corresponds to and contacts the first or second insulating portionof another piezoelectric unit.
 11. The multi-layer stacked-typepiezoelectric device according to claim 10, wherein each piezoelectricunit further comprises: a first insulation sidewall, connected to thefirst insulating portion and electrically isolating the conductivematerial in the first contact hole from the piezoelectric layer; and asecond insulation sidewall, connected to the second insulating portionand electrically isolating the conductive material in the second contacthole from the piezoelectric layer.
 12. The multi-layer stacked-typepiezoelectric device according to claim 10, wherein in eachpiezoelectric unit, an end of the first insulation sidewall is alignedwith the lower surface of the piezoelectric layer, and an end of thesecond insulation sidewall is aligned with the upper surface of thepiezoelectric layer.
 13. The multi-layer stacked-type piezoelectricdevice according to claim 10, wherein the conductive material is aconductive adhesive.
 14. The multi-layer stacked-type piezoelectricdevice according to claim 10, wherein the conductive material is silverpaste.
 15. The multi-layer stacked-type piezoelectric device accordingto claim 10, wherein the materials of the first and second insulatingportions comprise epoxy.
 16. A stacked-type piezoelectric device,comprising: a plurality of piezoelectric layers; a plurality ofconductive layers, formed between the piezoelectric layers; a firstcontact hole and a second contact hole, respectively penetrating thepiezoelectric layers and the conductive layers, wherein the first andsecond contact holes are filled with a conductive material; and aplurality of insulating portions, formed in the conductive layerscorrespondingly, and two adjacent insulating portions respectivelylocated at the outer rims of the first contact hole and the secondcontact hole, for electrically isolating the conductive layer in whichthe insulating portion is formed from the conductive material in thecontact hole.
 17. The multi-layer stacked-type piezoelectric deviceaccording to claim 16 further comprising n piezoelectric layers and(n+1) conductive layers, wherein n is a positive integer not less than2, the insulating portions on the odd-numbered conductive layers arecorresponding to the outer rim of the first contact hole, and theinsulating portions on the even-numbered conductive layers arecorresponding to the outer rim of the second contact hole.
 18. Themulti-layer stacked-type piezoelectric device according to claim 16further comprising: a plurality of insulation sidewalls disposed betweenthe piezoelectric layers and the first and second contact holes, forelectrically isolating the piezoelectric layer from the conductivematerial in the contact hole in which the insulation sidewalls areformed.
 19. The multi-layer stacked-type piezoelectric device accordingto claim 16, wherein the insulation sidewalls are connected to theadjacent insulating portions respectively.
 20. The multi-layerstacked-type piezoelectric device according to claim 16, wherein theconductive material is a conductive adhesive.
 21. The multi-layerstacked-type piezoelectric device according to claim 20, wherein theconductive material is silver paste.
 22. The multi-layer stacked-typepiezoelectric device according to claim 16, wherein the material of theinsulating portions comprises epoxy.
 23. A method for manufacturing asingle-layer piezoelectric device, the method comprising: providing apiezoelectric layer having an upper surface and a lower surface; forminga first conductive layer and a second conductive layer respectively onthe upper and lower surfaces of the piezoelectric layer; forming a firstcontact hole and a second contact hole respectively penetrating thefirst conductive layer, the piezoelectric layer and the secondconductive layer; forming a first insulating portion and a secondinsulating portion respectively on the first and second conductivelayers, and the first and second insulating portions respectivelylocated at the outer rims of the first and second contact holes; andfilling a conductive material in the first and second contact holes;wherein the first insulating portion electrically isolates the firstcontact hole from the first conductive layer, and the second insulatingportion electrically isolates the second contact hole from the secondconductive layer.
 24. The method according to claim 23 furthercomprising: forming a first insulation sidewall between the firstcontact hole and the piezoelectric layer, the first insulation sidewallconnected to the first insulating portion; and forming a secondinsulation sidewall between the second contact hole and thepiezoelectric layer, the second insulation sidewall connected to thesecond insulating portion.
 25. The method according to claim 24, whereinafter the step of providing the piezoelectric layer, a first penetratinghole and a second penetrating are formed on two lateral sides of thepiezoelectric layer; filling an insulating material in the first andsecond penetrating holes; forming the first and second conductive layersrespectively on the upper and lower surfaces of the piezoelectriclayers; drilling on the places corresponding to the first and secondpenetrating holes for forming the first and second contact holes, thediameter of the first and second contact holes being less than that ofthe first and second penetrating holes to form the first and secondinsulation sidewalls; removing a portion of the first conductive layercorresponding to the outer rim of the first contact hole, and removing aportion of the second conductive layer corresponding to the outer rim ofthe second contact hole; filling the insulating material in the firstand second contact hole; drilling the first and second contact holes forleaving the insulating material at the outer rims of the first andsecond contact holes to form the first and second insulating portion;and filling the conductive material in the first and second contactholes.
 26. The method according to claim 23, wherein after the step ofproviding the piezoelectric layer, the first and second conductivelayers are respectively formed on the upper and lower surfaces of thepiezoelectric layer; forming a first and a second penetrating holesrespectively penetrating two lateral sides of the first conductivelayer, the piezoelectric layer and the second conductive layer; removinga portion of the first conductive layer corresponding to the outer rimof the first penetrating hole, and removing a portion of the secondconductive layer corresponding to the outer rim of the secondpenetrating hole; filling an insulating material in the placescorresponding to the first and second penetrating holes, the insulatingmaterial fully filled in the removed portion of the first and secondconductive layers; drilling the first and second penetrating holes forforming the first and second contact holes, the diameter of the firstand second contact holes being the same as that of the first and secondpenetrating holes, wherein after the drilling step, the insulatingmaterial is at the outer rims of the first and second contact holes tobe the first and second insulating portions; and filling the conductivematerial in the first and second contact holes.
 27. A method formanufacturing a multi-layer stacked-type piezoelectric device, themethod comprising: manufacturing a plurality piezoelectric units, eachof the piezoelectric unit comprising: a piezoelectric layer, having anupper surface and a lower surface; a first conductive layer and a secondconductive layer, respectively located on the upper and lower surfacesof the piezoelectric layer; a first contact hole and a second contacthole, respectively penetrating two lateral sides of the first conductivelayer, the piezoelectric layer and the second conductive layer; and afirst insulating portion and a second insulating portion, respectivelyformed in the first conductive layer and the second conductive layer onthe upper and lower surfaces of the piezoelectric layer and at the outerrims of the first and second contact holes; stacking the piezoelectricunits, so that the first or second insulating portion of eachpiezoelectric unit contacts the first or second insulating portion of anadjacent piezoelectric unit, wherein the first contact holes and thesecond contact holes form a first channel and a second channel after thestacking step; and filling a conductive material in the first channeland the second channel, so that the first and second channels filledwith the conductive material respectively penetrate the piezoelectricunits.
 28. The method according to claim 27, wherein the step ofmanufacturing each of the piezoelectric unit further comprises: forminga first insulation sidewall between the first contact hole and thepiezoelectric layer, the first insulation sidewall connected to thefirst insulating portion; and forming a second insulation sidewallbetween the second contact hole and the piezoelectric layer, the secondinsulation sidewall connected to the second insulating portion.
 29. Themethod according to claim 27, wherein one piezoelectric unit is rotatedlaterally 180° and then stacked on another piezoelectric unit.
 30. Amethod for manufacturing a multi-layer stacked-type piezoelectric unit,the method comprising: manufacturing a plurality of first and secondinsulated piezoelectric bodies, each of the first and second insulatedpiezoelectric bodies comprising: a piezoelectric layer, having an uppersurface and a lower surface; a conductive layer, on the upper surface ofthe piezoelectric layer; and a first insulating material and a secondinsulating material, respectively formed at a left half and a right halfof the conductive layers of the first and second insulated piezoelectricbodies; staggeredly stacking the first and second insulatedpiezoelectric bodies, for forming a stacked-type assembly; drilling thestacked-type assembly at the places corresponding to the first andsecond insulating materials for forming a first channel and a secondchannel, and the size of the first and second channels being less thanthat of the first and second insulating materials, so that a firstinsulating portion and a second insulating portion are formed in theconductive layers of the first and second insulated piezoelectric bodiesrespectively after the drilling step; and filling a conductive materialin the first channel and the second channel, so that the first andsecond channels with the conductive material respectively penetrate theinsulated piezoelectric bodies.
 31. The method according to claim 30,wherein the first and second insulating materials are aligned with thesurfaces of the conductive layers in which the insulating materials areformed.
 32. The method according to claim 30, wherein the first andsecond insulating materials are formed by high temperature coating. 33.The method according to claim 30 further comprising performinghot-pressing sinter on the stacked-type assembly after the step offorming the stacked-type assembly.
 34. A method for manufacturing amulti-layer stacked-type piezoelectric device, the method comprising:manufacturing a plurality of first and second piezoelectric bodies, andeach of the piezoelectric bodies comprising: a piezoelectric layer,having an upper surface and a lower; and a conductive layer, formed onthe upper surface of the piezoelectric layer, the conductive layers ofthe first and second piezoelectric bodies respectively having a firstopening and a second opening, the first opening formed at the left halfof the piezoelectric layer correspondingly, the second opening formed atthe right half of the piezoelectric layer correspondingly, staggeredlystacking the first and second piezoelectric bodies for forming astacked-type assembly; drilling the stacked-type assembly correspondingto the first and second openings forming a first channel and a secondchannel, the size of the first and second channels being less than thatof the first and second openings; filling an insulating material in thefirst and second channels and the first and second openings; drillingthe first and second channels again for removing the insulatingmaterials in the first and second channels, a first insulating portionand a second insulating portion being respectively formed on theconductive layers of the first and second piezoelectric bodies after thedrilling step; and filling a conductive material in the first and secondchannels again.
 35. The method according to claim 34 further comprisingperforming hot-pressing sintering on the stacked-type assembly after thestep of forming the stacked-type assembly.
 36. The method according toclaim 34, wherein the conductive material filled in the first and secondchannels is a conductive adhesive.